I agree, it's hard but worth it. I have the data to back it up through sleep tracking. I've always felt somewhat unfazed by coffee, yet caffeine flashbacks can be very subtle and do seem to have a measurable impact on this "user" at least.

Also really darkening the bedroom and keeping the temperature as low as possible.

Now if there only were a consistent solution for energetic "night owl" toddlers to go with that ever more optimized regimen :D